Arizona-based start-up World View wants to fly tourists to the edge of space — 19 miles or 100,000 feet up — in a pressurized capsule suspended from a helium balloon. The balloon would take one and a half hours to ascend, and passengers would spend two hours admiring the view. “The sky’s going to be completely black. You’ll be able to see the curvature of the Earth,” said company CEO Jane Poynter. Test flights are scheduled for this year, and commercial flights are expected to cost $75,000 per ticket and begin in 2016.